1. Field of the Invention
This present invention relates to coating compositions containing polyisocyanates, polyaspartates and organic acids, which may be rapidly cured to provide coatings which have improved flexibility.
2. Description of the Prior Art
Two-component coating compositions containing, as binders, polyisocyanates in combination with polyaspartates containing secondary amino groups are known and disclosed in U.S. Pat. No. 5,126,170 and also DE-OS 2,158,945. They are suitable for the formation of high quality coatings and can be adjusted to produce coatings which are hard, elastic, abrasion resistant, solvent resistant and especially weather resistant. A disadvantage of these systems is that the coatings are not suitable for applications which require a high degree of flexibility.
Accordingly, it is an object of the present invention to provide coatings having increased flexibility. This object may be achieved with the coating compositions of the present invention which contain organic acids in addition to the polyisocyanates and polyaspartates. It is surprising that the addition of an organic acid would have any affect on the flexibility of the coating composition since the reaction product of the polyisocyanate and polyaspartate would be expected to be the same regardless of the presence of the organic acid.